1. Field of the Invention
The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus that provides a trailing end regulating member to be separated from a cassette body of a sheet cassette that stores sheets.
2. Description of the Related Art
In general, each of image forming apparatuses, such as a copying machine, a printer, and a facsimile, includes a sheet feeding apparatus. In this image forming apparatus, a sheet is fed from the sheet feeding apparatus to an image forming portion and an image is formed on the sheet by the image forming portion. The sheet feeding apparatus is generally configured as follows. A sheet cassette serving as a sheet storage portion is mounted in an image forming apparatus body to be drawn therefrom, and sheets stored in the sheet cassette is automatically fed to the image forming portion by a sheet feeding roller.
In this case, a cassette body where sheets of the sheet cassette are stored is provided with a trailing end regulating member. When a sheet that has a smaller size than a sheet having a maximum size where the sheet can be stored is stored, the trailing end regulating member regulates a position of an end of the stored sheet at an upstream side of a sheet feeding direction (hereinafter, simply referred to as a trailing end). Further, the sheet cassette body is provided with a side end regulating member that regulates a position of a side end of the sheet in a direction orthogonal to the sheet feeding direction (hereinafter, referred to as width-wise direction).
In addition, in the sheet cassette, the position of the side end of the sheet is regulated by the side end regulating member. Meanwhile, the trailing end of the sheet is regulated by the trailing end regulating member, such that a position of the tip of the sheet is always regulated to a predetermined sheet feedable position. As a result, when the sheet cassette is mounted in the image forming apparatus body, each sheet can be stably fed without depending on the size of each sheet.
In recent years, in order to improve spatial efficiency, the image forming apparatus has been miniaturized. However, when the image forming apparatus is miniaturized, due to the used sheet, that is, the sheet cassette, the image forming apparatus body may be shortened. In this case, if the sheet cassette is mounted in the image forming apparatus body, the sheet cassette may protrude from the image forming apparatus body, which results in deteriorating spatial efficiency.
Accordingly, in order to resolve the above-described problem, for example, Japanese Patent Application Laid-Open No. 2001-97561 discloses an expanding/contracting sheet cassette in which a trailing end regulating member is provided to be drawn from a cassette body and drawn in accordance with a size of a sheet.
In this case, in the expanding/contracting sheet cassette, the cassette body is formed to have a size smaller than or equal to a size of the image forming apparatus body. In addition, when a sheet that has a size larger than the size of the cassette body is stored, the trailing end regulating member is drawn by the amount of protrusion of the sheet from the image forming apparatus body.
In the sheet cassette according to the related art that has the above-described structure, the trailing end regulating member is locked by a locking member at the drawn position or a storage position. When the trailing end regulating member is drawn or the sheet is stored, locking of the locking member is released.
Further, in order to store a sheet having a small size in the sheet cassette, the trailing end regulating member is divided into two parts. That is, one of the two parts is used as a trailing end regulating member for a large size and the other is used as a trailing end regulating member for a small size. Further, the cassette body is provided with a middle plate needed to press the sheet by the sheet feeding roller. However, in the middle plate, a slit is provided to enable a movement of the trailing end regulating member for the small size. In addition, the trailing end regulating member for the small size is provided to have a size smaller than a size of the trailing end regulating member for the large size, such that the trailing end regulating member of the small size can move in the slit.
FIG. 22 is a perspective view illustrating an expanding/contracting sheet cassette according to the related art. In FIG. 22, an expanding/contracting sheet cassette 102, a cassette body 103, and a first trailing end regulating member 104 are illustrated. In this case, the first trailing end regulating member 104 is provided in the cassette body 103 to be slid. The first trailing end regulating member 104 includes a locking member (not illustrated) that locks the first trailing end regulating member 104 to the cassette body 103, and a locking releasing lever 106 that releases locking by the locking member and is used for the first trailing end regulating member.
A second trailing end regulating member 105 for a small size is provided in the first trailing end regulating member 104 to be slid. The second trailing end regulating member 105 includes a locking member (not illustrated) that locks the second trailing end regulating member 105 to the cassette body 103 and a locking releasing lever 107 that releases locking by the locking member and is used for the second trailing end regulating member. A middle plate 108 is provided in the cassette body 103 to rotate in an upward-to-downward direction. The middle plate 108 is provided with a slit 108a where the second trailing end regulating member 105 enters.
In addition, when the sheet is stored in the sheet cassette 102, locking of the first and second trailing end regulating members 104 and 105 are released by the locking releasing levers 106 and 107, and the first and second trailing end regulating members 104 and 105 are moved to positions according to the size of the sheet.
For example, when a sheet having a small size is stored, only the second trailing end regulating member 105 enters into a slit that is formed in the middle plate 108, as illustrated in FIG. 23A. Further, when a sheet having a large size is stored, the first and second trailing end regulating members 104 and 105 are drawn from the cassette body 103, as illustrated in FIG. 23B.
However, in the image forming apparatus according to the related art that includes the sheet cassette, works for moving the two trailing end regulating members 104 and 105 are independently performed. For this reason, when a sheet that has a size different from the size of the sheets stored until now is stored in the sheet cassette, it is needed to operate both the first trailing end regulating member 104 and the second trailing end regulating member 105 after releasing locking.
That is, in the sheet cassette according to the related art, when the size of the sheet is changed, a user needs to operate the two locking releasing levers 106 and 107 to perform expanding/contracting operations of the first and second trailing end regulating members 104 and 105, which results in lowering usability.
Accordingly, the present invention provides an image forming apparatus that can improve usability.